Uncoupling of behavioral and metabolic 24-h rhythms in reindeer

Reindeer in the Arctic seasonally suppress daily circadian patterns of behavior present in most animals.1 In humans and mice, even when all daily behavioral and environmental influences are artificially suppressed, robust endogenous rhythms of metabolism governed by the circadian clock persist and are essential to health.2,3 Disrupted rhythms foster metabolic disorders and weight gain.4 To understand circadian metabolic organization in reindeer, we performed behavioral measurements and untargeted metabolomics from blood plasma samples taken from Eurasian tundra reindeer (Rangifer tarandus tarandus) across 24 h at 2-h intervals in four seasons. Our study confirmed the absence of circadian rhythms of behavior under constant darkness in the Arctic winter and constant daylight in the Arctic summer, as reported by others.1 We detected and measured the intensity of 893 metabolic features in all plasma samples using untargeted ultra-high-performance liquid chromatography-mass spectrometry (UPLC-MS). A core group of metabolites (66/893 metabolic features) consistently displayed 24-h rhythmicity. Most metabolites displayed a robust 24-h rhythm in winter and spring but were arrhythmic in summer and fall. Half of all measured metabolites displayed ultradian sleep-wake dependence in summer. Irrespective of the arrhythmic behavior, metabolism is rhythmic (24 h) in seasons of low food availability, potentially favoring energy efficiency. In seasons of food abundance, 24-h rhythmicity in metabolism is drastically reduced, again irrespective of behavioral rhythms, potentially fostering weight gain.

Wake EEG oscillation dynamics reflect both sleep need and brain maturation across childhood and adolescence

An objective measure of brain maturation is highly insightful for monitoring both typical and atypical development. Slow wave activity, recorded in the sleep electroencephalogram (EEG), reliably indexes changes in brain plasticity with age, as well as deficits related to developmental disorders such as attention-deficit hyperactivity disorder (ADHD). Unfortunately, measuring sleep EEG is resource-intensive and burdensome for participants. We therefore aimed to determine whether wake EEG could likewise index developmental changes in brain plasticity. We analyzed high-density wake EEG collected from 163 participants 3-25 years old, before and after a night of sleep. We compared two measures of oscillatory EEG activity, amplitudes and density, as well as two measures of aperiodic activity, intercepts and slopes. Furthermore, we compared these measures in patients with ADHD (8-17 y.o., N=58) to neurotypical controls. We found that wake oscillation amplitudes behaved the same as sleep slow wave activity: amplitudes decreased with age, decreased after sleep, and this overnight decrease decreased with age. Oscillation densities were also substantially age-dependent, decreasing overnight in children and increasing overnight in adolescents and adults. While both aperiodic intercepts and slopes decreased linearly with age, intercepts decreased overnight, and slopes increased overnight. Overall, our results indicate that wake oscillation amplitudes track both development and sleep need, and overnight changes in oscillation density reflect some yet-unknown shift in neural activity around puberty. No wake measure showed significant effects of ADHD, thus indicating that wake EEG measures, while easier to record, are not as sensitive as those during sleep.

Reindeer in the Arctic reduce sleep need during rumination

Timing and quantity of sleep depend on a circadian (∼24-h) rhythm and a specific sleep requirement.1 Sleep curtailment results in a homeostatic rebound of more and deeper sleep, the latter reflected in increased electroencephalographic (EEG) slow-wave activity (SWA) during non-rapid eye movement (NREM) sleep.2 Circadian rhythms are synchronized by the light-dark cycle but persist under constant conditions.3,4,5 Strikingly, arctic reindeer behavior is arrhythmic during the solstices.6 Moreover, the Arctic's extreme seasonal environmental changes cause large variations in overall activity and food intake.7 We hypothesized that the maintenance of optimal functioning under these extremely fluctuating conditions would require adaptations not only in daily activity patterns but also in the homeostatic regulation of sleep. We studied sleep using non-invasive EEG in four Eurasian tundra reindeer (Rangifer tarandus tarandus) in Tromsø, Norway (69°N) during the fall equinox and both solstices. As expected, sleep-wake rhythms paralleled daily activity distribution, and sleep deprivation resulted in a homeostatic rebound in all seasons. Yet, these sleep rebounds were smaller in summer and fall than in winter. Surprisingly, SWA decreased not only during NREM sleep but also during rumination. Quantitative modeling revealed that sleep pressure decayed at similar rates during the two behavioral states. Finally, reindeer spent less time in NREM sleep the more they ruminated. These results suggest that they can sleep during rumination. The ability to reduce sleep need during rumination-undisturbed phases for both sleep recovery and digestion-might allow for near-constant feeding in the arctic summer.

Functional networks of working memory abilities in children with complex congenital heart disease: a sleep EEG study

Working memory is frequently impaired in children with complex congenital heart disease (CHD), but little is known about the functional neuronal correlates. Sleep slow wave activity (SWA; 1-4.5 Hz EEG power) has previously been shown to reliably map neurofunctional networks of cognitive abilities in children with and without neurodevelopmental impairments. This study investigated whether functional networks of working memory abilities are altered in children with complex CHD using EEG recordings during sleep. Twenty-one children with complex CHD (aged 10.9 [SD: 0.3] years) and 17 typically-developing peers (10.5 [0.7] years) completed different working memory tasks and an overnight high-density sleep EEG recording (128 electrodes). The combined working memory score tended to be lower in children with complex CHD (CHD group: -0.44 [1.12], typically-developing group: 0.55 [1.24], d = 0.59, p = .06). The working memory score and sleep SWA of the first hour of deep sleep were correlated over similar brain regions in both groups: Strong positive associations were found over prefrontal and fronto-parietal brain regions - known to be part of the working memory network - and strong negative associations were found over central brain regions. Within these working memory networks, the associations between working memory abilities and sleep SWA (r between -.36 and .58, all p < .03) were not different between the two groups (no interactions, all p > .05). The current findings suggest that sleep SWA reliably maps working memory networks in children with complex CHD and that these functional networks are generally preserved in these patients.

First results of spatial reconstruction and quantification of COVID-19 chest CT infiltrates using lung CT analyzer and 3D slicer

Objective

Lung CT scans are early diagnostic tests in evaluation of COVID-19 patients. Data are usually analyzed visually and the extent of infiltrations can only roughly be estimated. The aim of the present study was to create a software to spatially visualize and quantify infiltrated and collapsed areas in lung CT scans and set these volumes into relation with non-affected lung areas.

Methods

A new software "Lung CT Analyzer" (LCTA, 1) was created from scratch in an international team-effort within the 3D medical imaging software 3D Slicer (2). LCTA consists of two components: "Lung CT Segmenter" implements an intuitive and semiautomatic workflow for the generation of lung masks. LCTA then uses masked thresholds of Hounsfield units to detect non-affected versus affected (emphysematous, infiltrated, and collapsed) areas of the lung. Intrapulmonary vessels are subtracted from the other volumes. Segment volumes are expressed in milliliters and displayed in 3D. COVID-Q was defined as affected divided by non-affected volume and can be calculated separately for both lungs.

3D Slicer and LCTA are open source, freely available and maintained on Github.

Results

CT data of twelve patients with moderate to severe COVID-19 (9 m, 3 f) were selected for the present retrospective study. All scans were performed shortly after admission. Thresholds of Hounsfield units (HU) for areas of interest were defined prior to the study and processing was identical for all patients. The median time effort for 3D reconstruction was 8 minutes per patient. For more detailed results please see the enclosed table. A 3D Slicer demo data set (Control) has been included for comparison.

Conclusion

The COVID-19 pandemic promoted fast-paced innovations such as LCTA in our hospital. LCTA was feasible, reproducible and easy to perform. COVID-Q correlated with COVID-19 lung involvement in all cases. All fatal cases showed COVID-Q values of > 2.0.

LCTA enabled the serial 3D reconstruction of infiltrated and collapsed lung areas in lung CT scans. The procedure may be of great help in the future analysis of pulmonary infiltrates of any cause. In COVID-19 disease, volumetric lung CT reconstruction could result in the definition of new prognostic factors, identify patients “at-risk” in the ICU, and be useful for follow-up.

(1) Lung CT Analyzer: https://github.com/rbumm/SlicerLungCTAnalyzer

(2) 3D Slicer: http://slicer.org

Surgical innovation revisited: A historical narrative of the minimally invasive “Agarwal sliding‐clip renorrhaphy” technique for partial nephrectomy and its application to an Australian cohort

Objective

To evaluate local clinical outcomes of sliding clip renorrhaphy, from inception to current utilization for open, laparoscopic, and robotically assisted partial nephrectomy.

Methods

We reviewed prospectively maintained databases of three surgeons performing partial nephrectomies with the sliding‐clip technique at teaching hospitals between 2005 and 2019. Baseline characteristics, operative parameters, including surgical approach, RENAL Nephrometry Score, and post‐operative outcomes, including Clavien‐Dindo classification of complications, were recorded for 76 consecutive cases. We compared perioperative and 90‐day events with patient and tumor characteristics, stratified by operative approach and case complexity, using Wilcoxon rank‐sum test for continuous variables and the Chi‐squared or Fisher's exact test, for binary and categorical variables, respectively.

Results

Open surgery (n = 15) reduced ischemia time and operative time, but increased hospital admission time. Pre‐ and post‐operative estimated glomerular filtration rates did not change significantly by operative approach. Older patients (P = .007) and open surgery (P = .003) were associated with a higher rate of complications (any‐grade). Six grade ≥3 complications occurred: these were associated with higher RENAL Nephrometry Score (P = .016) and higher pathological tumor stage (P = .045). Limits include smaller case volumes which incorporate the learning curve cases; therefore, these data are most applicable to lower volume teaching hospitals.

Conclusion

The sliding‐clip technique for partial nephrectomy was first described by Agarwal et al and has low complication rates, acceptable operative time, and preserves renal function across open and minimally invasive surgeries. This series encompasses the initial learning curve with developing the technique through to present‐day emergence as a routine standard of practice.

Characterization of overnight slow-wave slope changes across development in an age-, amplitude-, and region-dependent manner

STUDY OBJECTIVES

The restorative function of sleep has been linked to a net reduction in synaptic strength. The slope of slow-waves, a major characteristic of non-rapid eye movement (NREM) sleep, has been shown to directly reflect synaptic strength, when accounting for amplitude changes across the night. In this study, we aimed to investigate overnight slope changes in the course of development in an age-, amplitude-, and region-dependent manner.

METHODS

All-night high-density electroencephalography data were analyzed in a cross-sectional population of 60 healthy participants in the age range of 8-29 years. To control for amplitude changes across the night, we matched slow-waves from the first and the last hour of NREM sleep according to their amplitude.

RESULTS

We found a reduction of slow-wave slopes from the first to the last hour of NREM sleep across all investigated ages, amplitudes, and most brain regions. The overnight slope change was largest in children and decreased toward early adulthood. A topographical analysis revealed regional differences in slope change. Specifically, for small amplitude waves the decrease was smallest in an occipital area, whereas for large amplitude waves, the decrease was smallest in a central area.

CONCLUSIONS

The larger slope decrease in children might be indicative of a boosted renormalization of synapses during sleep in childhood, which, in turn, might be related to increased plasticity during brain maturation. Regional differences in the extent of slow-wave slope reduction may reflect a "smart" down-selection process or, alternatively, indicate amplitude-dependent differences in the generation of slow-waves.

The experience-dependent increase in deep sleep activity is reduced in children with attention-deficit/hyperactivity disorder

OBJECTIVE/BACKGROUND

Learning of a visuomotor adaptation task during wakefulness leads to a local increase in slow-wave activity (SWA, EEG power between 1 and 4.5 Hz) during subsequent deep sleep. Here, we examined this relationship between learning and SWA in children with attention-deficit/hyperactivity disorder (ADHD).

PATIENTS/METHODS

Participants were 15 children with ADHD (9.7-14.8 y, one female) and 15 age-matched healthy controls (9.6-15.7 y, three female). After the completion of a visuomotor adaptation task in the evening, participants underwent an all-night high-density (HD, 128 electrodes) sleep-EEG measurement.

RESULTS

Healthy control children showed the expected right-parietal increase in sleep SWA after visuomotor learning. Despite no difference in visuomotor learning, the local up-regulation during sleep was significantly reduced in ADHD patients compared to healthy controls.

CONCLUSIONS

Our results indicate that the local, experience-dependent regulation of SWA is different in ADHD patients. Because the customarily observed heightened regulation in children was related to sensitive period maturation, ADHD patients may lack certain sensitive periods or show a developmental delay.

Reduced sleep spindle density in adolescent patients with early-onset schizophrenia compared to major depressive disorder and healthy controls

OBJECTIVES

During adolescence schizophrenia and major depressive disorder (MDD) increasingly emerge. Overlapping symptomatology during first presentation challenges the diagnostic process. Reduced sleep spindle density (SSD) was suggested as a biomarker in adults, discerning patients with schizophrenia from patients with depression or healthy controls (HC). We aimed to compare SSD in early-onset schizophrenia (EOS), with MDD, and HC, and to analyse associations of SSD with symptomatology and neurocognitive measures.

METHODS

Automatic sleep spindle detection was performed on all-night high-density EEG (128 electrodes) data of 12 EOS, 19 MDD, and 57 HC (age range 9.8-19), allowing an age- and sex-matching of 1:2 (patients vs. HC). Severity of current symptoms and neurocognitive variables were assessed in all patients.

RESULTS

SSD was defined between 13.75 and 14.50 Hz as within this frequency range SSD differed between EOS vs. HC in bin by bin analyses (12-15 Hz). In EOS, SSD was lower over 27 centro-temporal electrodes compared to HC and over 9 central electrodes compared to MDD. Reduced SSD in EOS compared to MDD and HC was accompanied by a high variability of SSD in all adolescents. SSD did not differ between MDD and HC. In the pooled sample of patients, lower SSD was associated with more severe Positive and Negative Symptoms Scale total score, more impaired memory consolidation and processing speed.

CONCLUSION

A high variability of SSD in all adolescents may reflect the evolving character of SSD. The association of reduced SSD with the symptom dimension of impaired cognition cuts across diagnostical entities.

Radial nerve palsy in humeral shaft fractures with internal fixation: analysis of management and outcome

INTRODUCTION

The incidence of radial nerve injury after humeral shaft fractures is on average 11.8% (Shao et al., J Bone Jt Surg Br 87(12):1647-1652, 2005) representing the most common peripheral nerve injury associated with long bone fractures (Korompilias et al., Injury, 2013). The purpose of this study was to analyze our current policy and long-term outcome, regarding surgically treated humeral shaft fractures in combination with radial nerve palsy.

MATERIALS AND METHODS

We retrospectively analyzed the data of patients with surgically treated humeral shaft fractures from 01/01/2003 to 28/02/2013. The analysis included fracture type, soft tissue injury regarding closed and open fractures, type of fixation, management, and outcome of radial nerve palsy.

RESULTS

A total of 151 humeral shaft fractures were fixed in our hospital. In 20 (13%) cases, primary radial palsy was observed. Primary nerve exploration was performed in nine cases. Out of the 13 patients with follow-up, 10 showed a complete, 2 a partial, and 1 a minimal nerve recovery. Two of them underwent a revision procedure. Secondary radial nerve palsy occurred in 9 (6%) patients postoperatively. In five patients, the radial nerve was not exposed during the initial surgery and, therefore, underwent revision with nerve exploration. In all 5, a potential cause for the palsy was found and corrected as far as possible with full recovery in 3 and minimal recovery in one patient. In four patients with exposure of the nerve during the initial surgery, no revision was performed. All of these 4 showed a full recovery.

CONCLUSION

Our study showed an overall rate of 19% radial nerve palsy in surgically treated humeral shaft fractures. Most of the primary palsies (13%) recovered spontaneously, and therefore, nerve exploration was only exceptionally needed. The incidence of secondary palsy after surgery (6%) was high and mainly seen after plate fixation. In these cases, we recommend early nerve exploration, to detect and treat potential curable neural lesions.

[Solitary pulmonary nodule on CT - observation or surgical resection?]

Incidentally found solitary pulmonary nodules (SPN) are increasing due to liberal use of high resolution CT scans. SPNs are defined as densities up to 3cm without associated enlarged lymph nodes. Morphologic patterns of the SPN in CT or dynamic changes in serial investigations as well as the individual risk profile (age, smoking history, current or past malignant disease) are crucial to classify the likelihood of malignancy as low, intermediate or high. Whereas low risk SPNs have to be observed by serial CT scans, intermediate risk SPNs have to be evaluated by transthoracic or bronchoscopic biopsies. However, these investigations are only reliable if malignant or specific benign diseases can be clearly diagnosed in the obtained tissue. In all the other cases, SPNs remain undetermined and surgical resection is mandatory. Increasingly, FDG-PET is performed in patients with intermediate risk SPNs and a high risk for surgery aiming to further determine the pre-test probability of malignant disease. Its sensitivity is about 80%. Nodules with high FDG uptake are suspect to be malignant and surgical removal is indicated. SPN with a high likelihood to be malignant are usually resected surgically as a primary approach. In case of metastasis, excisional biopsy may be therapeutic. The surgical method of choice is the video assisted thoracoscopic (VATS) wedge resection. Ideal for this method are nodules of 1 to 2 cm in diameter not localised deeper within lung parenchyma than its own diameter. If a SPN is diagnosed intraoperatively to be a non-small cell lung cancer, anatomic resection can be performed under the same anaesthesia. SPNs diagnosed to be cancer often are early stage tumours. Therefore, lobectomy and lymphadenectomy can also be made in VATS technique. In rare cases, diagnostic thoracotomy may still be necessary to definitely determine the aetiology of a SPN. An interdisciplinary approach is crucial to plan an efficient and individualised work-up of SPNs.

Challenging narrow distal aorta in abdominal aortic aneurysm--endovascular repair using a reversed flared endoprosthesis

INTRODUCTION

Narrow aortic bifurcations are a challenging issue while treating abdominal aortic aneurysm by endovascular means. Off-the-shelf products are often not suitable and special considerations and custom-made endoprostheses are necessary.

REPORT

Alternatively, some morphologies qualify for a flared tube graft. We report two successful aneurysm exclusions using custom-made (Anaconda, Vascutek/Terumo) step-down diameter grafts in patients with tight distal aortas without the need for pre-interventional endograft adjustments.

DISCUSSION

In these two cases, implantation of a custom-made proximally flared tube endograft in treating a localised abdominal aortic aneurysm with a narrow and calcified bifurcation seems feasible. They represent uncommon, yet challenging, issues worthy of attention.

Prognostic factors affecting long-term outcomes in patients with resected stage IIIA pN2 non-small-cell lung cancer: 5-year follow-up of a phase II study

The aim was to investigate the efficacy of neoadjuvant docetaxel-cisplatin and identify prognostic factors for outcome in locally advanced stage IIIA (pN2 by mediastinoscopy) non-small-cell lung cancer (NSCLC) patients. In all, 75 patients (from 90 enrolled) underwent tumour resection after three 3-week cycles of docetaxel 85 mg m-2 (day 1) plus cisplatin 40 or 50 mg m-2 (days 1 and 2). Therapy was well tolerated (overall grade 3 toxicity occurred in 48% patients; no grade 4 nonhaematological toxicity was reported), with no observed late toxicities. Median overall survival (OS) and event-free survival (EFS) times were 35 and 15 months, respectively, in the 75 patients who underwent surgery; corresponding figures for all 90 patients enrolled were 28 and 12 months. At 3 years after initiating trial therapy, 27 out of 75 patients (36%) were alive and tumour free. At 5-year follow-up, 60 and 65% of patients had local relapse and distant metastases, respectively. The most common sites of distant metastases were the lung (24%) and brain (17%). Factors associated with OS, EFS and risk of local relapse and distant metastases were complete tumour resection and chemotherapy activity (clinical response, pathologic response, mediastinal downstaging). Neoadjuvant docetaxel-cisplatin was effective and tolerable in stage IIIA pN2 NSCLC, with chemotherapy contributing significantly to outcomes.

[Acute vascular occlusion of the upper extremity after blunt trauma]

Intimal ruptures after blunt trauma without joint dislocation are rare. We report the case of a 62 year old male patient presenting with paraesthesia in the fingers I to III and a cool left hand after a blunt trauma of the upper arm. Non-invasive examination documented the thrombotic occlusion of the axillary artery. Due to a circular rupture of the intima surgical revascularization was performed with a vein graft.

Critical incident reporting system

Systems that record critical incidents were initially developed for aeronautics and are being increasingly applied in medicine. The objective is to detect problems inherent to systems and system errors before they lead to complications or do harm to patients. We report our preliminary experience with a critical incident reporting system (CIRS). Since February 1 2001, all employees of our surgical department have been able to report incidents, anonymously or candidly, to a central board using a standardized documentation form. The results are presented at monthly internal quality meetings, where two to three crucial incidences are thoroughly discussed. New information is communicated and put into practice as quickly as possible. A total of 424 incidents were reported from February 1, 2001 to December 31, 2003. Reversible damages, some of which resulted in prolonged hospitalization, were consequential to 22% of the cases. Thirteen percent were classified as "near miss" (almost incidents), whereas 65% had no consequences for patients. As expected, doctors and nurses were most frequently involved, as 36% of the reported incidents occurred in connection with the prescription and administration of medication. In particular, the near miss category revealed system errors which in 85% of cases had immediate consequences for therapeutic procedures. Based on our initial experiences, working with CIRS may be evaluated as positive. The open discussion of incidents and errors also revealed minor but often significant system errors, which resulted in alteration of our internal proceedings and thus improved the quality and safety of treatment.

[The role of video-thoracoscopy in thoracic surgery]

The widespread acceptance of minimal invasive techniques has revolutionized the practice of surgery including, thoracic surgery. Within a short period of time, video-assisted thoracic surgery (VATS) has become an acceptable approach to a wide range of thoracic procedures. The use of VATS as a diagnostic modality is now well established. For therapeutic procedures, VATS has also been generally accepted as the treatment for spontaneous pneumothorax, thoracic sympathectomy, treatment of loculated effusions and resection of simple mediastinal cysts and benign tumors. Its role in major procedures, e.g. anatomic lung resections and thymectomy, however, remain poorly defined at present although some of the existing intermediate results are encouraging. The technique continues to evolve, with further miniaturization to reduce access-induced trauma. No matter how attractive the new techniques may appear, carefully conducted clinical trials should precede the general acceptance and widespread use.

[Surgical management of abdominal aortic aneurysms with coexistent intestinal disease]

The management of patients suffering from abdominal aortic aneurysms with concomitant intestinal disease is demanding. Surgical procedures have to be evaluated meticulously with regard to morbidity and priority. We retrospectively investigated early and late results of nine patients (eight males, one female) with coincidental aortic and intestinal surgery during the last 9.5 years. The average age was 77 years (range 67-85). One-stage procedures were undertaken twice with implantation of aortic grafts to replace abdominal aortic aneurysms (AAA). During these emergency procedures, an aortoduodenal fistula was repaired in one case and resection of an ischemic segment of the sigmoid colon was resected in another. Seven two-stage procedures were performed as elective surgery. Five AAA were excluded before the intestinal repair. In two cases of urgent visceral pathologies, colon resection was done first, followed by elimination of the AAA. In case of elective surgery, two-stage procedures seem to be safe and effective. However, in certain emergent cases, one-stage procedures with implantation of vascular grafts in combination with colon or bowel surgery might also be justified.

[Severe heart failure: treatment optimisation and monitoring using plasma NT-proBNP levels--an useful tool in clinical practice]

A young patient presented with a cardiomegaly of unknown origin. The cardiologic examination revealed a severe eccentric left ventricular hypertrophy and a dilatation of the other heart cavities as well as a strongly impaired global systolic function. The patient was treated with an ACE inhibitor, a diuretic and with a beta-blocking agent. The dosages of which were adapted accordingly to the plasma concentration of N-terminal-pro-brain-natriuretic peptide (NT-proBNP). After five months of treatment, a decrease of the NT-proBNP level to nearly normal values along with a significant reduction of the heart dimensions and a substantial improvement of left ventricular function were found.

[Bilateral popliteal artery entrapment syndrome. Is preventive operation on the asymptomatic side indicated?]

Popliteal artery entrapment is a rare cause of claudication symptoms, but should always be included in the differential diagnosis of lower limb ischaemia in young patients, especially men. On an embryological basis, PAES is the result of the abnormal development of the popliteal artery or the gastrocnemius muscle. The anomaly is manifested as one of four types. Untreated, the entrapment results in the deterioration of the artery, resulting in eventual occlusion. Presenting the case of a 37 year old female patient with bilateral PAES and a review of the literature we discuss the clinical findings, diagnosis, treatment options and the management of the often asymptomatic opposite side.

[Merkel cell carcinoma. Retrospective analysis of 4 cases with special reference to diagnosis, therapy and long-term outcome]

BACKGROUND

Merkel cell carcinoma is an aggressive neuro-endocrine skin tumor with early regional lymph node involvement and early distant metastases. Diagnostic work-up may be difficult because of the low incidence of the tumor. Treatment concepts are individual and long-term-outcome are varying markedly.

METHODS

Retrospective analyse of four cases with special regard to the diagnostic, therapeutic approach and the long-term follow-up.

RESULTS

In every case diagnosis has only been made histologically. In the first patient, suffering from a tumor on the upper arm, after the tumor removal, local and axillary radiotherapy has been performed. In a second case with an extended tumor on the shank, a palliative tumor-debulking was followed by a chemo- and radiotherapy. The third Patient had a tumor in the gluteal region with involvement of the regional lymph nodes. He was treated by a complete surgical excision and lymphadenectomy followed by a local radiotherapy with subsequent chemotherapy. The fourth patient with tumor on the elbow, without lymph node involvement, refused surgical intervention, therefore she has been treated by radio- and chemotherapy. All patients are respectively 1.2 and 3 years are alive without evidence of recurrence. One patient died after 1.5 year because of tumor relapse.

CONCLUSION

Diagnosis of Merkel cell carcinoma is difficult and is established only by in- or excision biopsy of the tumor. If ever possible surgical excision combined with regional lymphadenectomy should be performed. Adjuvant radiotherapy is established, whereas the value of chemotherapy has not yet be defined and might be beneficial only in cases of expansive or disseminated growth. In our series we did encounter the often described metastatic involvement of other organs just in one case.

[How often do surgical residents operate in a category A non-university post-graduate teaching hospital?]

INTRODUCTION

After introduction of the new postgraduate training program for general surgery the completion of the operation list still represents the most important step. Based on our number of operations we examined whether residents would carry out the requested interventions at our non-university teaching hospital (category A).

METHOD

For eight tracer operations we retrospectively counted the number of cases of the non private patients from 1998-2002 and took account of the postgraduate education status of the operator. In this period the team consisted of 51 residents (71 education years), of whom 18 candidates for general surgery who carried out the interventions (35 education years, inclusive rotation in ICU, emergency room and special surgical disciplines).

RESULTS

Regarding all tracer operations, the amount of interventions per year and candidate which are necessary to accomplish the goal for the first four years of education are reached: appendectomy 8.9, laparoscopic cholecystectomy 7.3, open inguinal hernia repair 9.4, varicose veins operation 12.1, open colon sigmoideum resection 3.2, hip and malleolar fracture 6.9, hemithyreoidectomy 5.

CONCLUSION

Completion of the operation list as the major training goal was reached at our institution. Following our structured education program the demands regarding postgraduate education will be met also in future. Further studies however, must examine the impact of the new resident's work contracts dictating a reduction of the weekly working hours.

Haemophilus influenzae infections among hospitalized adult patients

BACKGROUND

Relatively few data are available about Haemophilus influenzae (Hi) infection among adults.

MATERIALS AND METHODS

We studied all adult patients with Hi infection hospitalized between 1988 and 1997 at the University Hospital of Berne. Data were abstracted retrospectively from clinical charts and microbiology records using a standardized questionnaire.

RESULTS

12 invasive and 19 noninvasive Hi infections were observed during the study period. The main clinical manifestations were pneumonia (38.7%), bronchitis (29.0%) and meningitis (12.9%). Most patients (71.8%) had an underlying condition. Lethality was high (22.6%), especially in pneumonia patients (50%). The frequency of meningitis caused by Hi serotype b (Hib) seemed to decrease after 1990 when conjugated vaccines against Hib were introduced.

CONCLUSION

Hi remains an important cause of lower respiratory and invasive disease associated with high lethality among polymorbid adult patients. The frequency of Hib infections may also decrease in adults due to herd immunity induced by universal vaccination of children.

[The indications for and results of video thoracoscopic sympathectomy]

BACKGROUND AND OBJECTIVES

Thoracoscopic sympathectomy, for years an effective way to treat mainly palmar and axilla hyperhidrosis, experienced a revival since the application of the principles of minimally invasive surgery. We report the personal experiences of three surgeons with this technique, as well as patients' view of the outcome.

PATIENTS AND METHODS

Between January 1990 and November 1997, 73 procedures were performed in 43 patients (23 males, 20 females, mean age 38.1 years, range 15-82 years), and the outcome was prospectively studied. Palmar hyperhidrosis without axilla symptoms was the indication for the operation in 27 patients (54 sympathectomies), Raynaud's syndrome in 15 (18 sympathectomies), and causalgia in one. Thoracic ganglia 2-4 were always completely resected. Perioperative morbidity as well as patient satisfaction in the long-term course (standardized interview) 25.8 (1-77) months postoperatively were assessed.

RESULTS

The complication rate in all 73 sympathectomies was 8.2%. Only two severe incidents were observed: in one patient intermittent Horner's syndrome (1.4%) occurred, and in another severe bleeding required conversion to open surgery (1.4%). Both complications occurred in the early study phase. The initial success rate in all 27 patients with hyperhidrosis was 100%. In 30% of these cases a mild partial relapse was observed, which did not interfere with their daily activities. 53% of the patients reported compensatory and 23% gustatory sweating. 9% would have refused the operation, had they known these side effects. In all patients with Raynaud's disease the ulcerations healed completely. At the time of the interview, two patients (13%) complained of painless relapses. They too stated that they had refused the operation, if they had known about the relapses.

CONCLUSIONS

Even in the longer-term course, thoracoscopic sympathectomy is rated subjectively successful by 93% of patients after treatment of hyperhidrosis of the upper extremities, and by 87% of patients after treatment of Raynaud's disease, despite some untoward effects and partial relapses.

Functional assessment of chest wall integrity after methylmethacrylate reconstruction

BACKGROUND

All patients with extensive resection of the anterolateral chest wall and the sternum followed by reconstruction with methylmethacrylate substitutes were assessed prospectively 6 months after the operation to delineate chest wall integrity with pulmonary function and cine-magnetic resonance imaging.

METHODS

Twenty-six patients underwent chest wall reconstruction by use of methylmethacrylate between 1994 and 1998 due to primary tumors in 35%, metastases in 27%, T3 lung cancer in 19%, and debridement for radionecrosis and osteomyelitis in 19% of patients. Three to eight ribs were resected and additional sternum resection was performed in 39% of patients.

RESULTS

There was no 30-day mortality. All patients were extubated after the operation without need for reintubation. Prosthesis dislocation occurred in 1 patient and infection in 2 patients during follow-up. Nineteen patients (73%) suffered no restrictions of daily activities. Clinical examination revealed normal shoulder girdle function in 77% of patients. There was no significant difference between preoperative and postoperative FEV1 (forced expiratory volume in 1 second) measurements in patients with lobectomy or wedge resections. Cinemagnetic resonance imaging revealed concordant chest wall movements during respiration in 92% of patients without paradoxical movements or implant dislocations being observed.

CONCLUSIONS

Large defects of the anterolateral chest wall and sternum can be reconstructed efficiently with methylmethacrylate substitutes with minimal morbidity and excellent cosmetic and functional outcome.

Is the function of the serratus anterior muscle disturbed following division during a standard thoracotomy?

In a prospective study the functional results after dissection or preservation of the serratus anterior muscle in the postero-lateral standard thoracotomy were evaluated. In 14 patients of our clinic with dissection and suture and in 14 patients with preservation of the serratus muscle the muscle function was assessed and compared preoperatively, within the first two post-operative weeks, and three months after the operation by the same physiotherapists. The two groups were blinded in regard to age, original disease, and mode of intervention. We compared the wing position of the scapula in the sitting position and the positioning of the scapula at fixation of the shoulder joint in the sitting and in the supine position. Using a four-grade function assessment scheme, both groups obtained the same functional results. There was no seroma in either group. After 2.8 (2.5 to 3.0) years all the surviving patients described symmetric functional conditions. We therefore conclude that in order to achieve a better view of the operative field the serratus muscle may be dissected close to the origin if it is then readapted.

[Surgical diagnosis and therapy in patients with mediastinal space-occupying lesions. A retrospective analysis of 223 intervention with special reference to long-term course]

The diagnostic and therapeutic approach in patients with mediastinal masses (MM) treated at our institute between 1983 and 1993 was retrospectively reviewed.

METHODS AND MATERIAL

193 patients with MM (105 males and 88 females, average age 53, ranging from 16-81) underwent 223 interventions. Staging mediastinoscopies in lung cancer patients were ruled out. Long-term follow-up data were available in 123 of 162 cases with neoplastic MM (average follow-up time 5.5 years). Of all 223 surgical interventions 143 were diagnostic (53 parasternal mediastinotomies, 78 mediastinoscopies and 8 thoracoscopies) and 80 therapeutic (46 sternotomies and 34 posterolateral and a second half). The analysed period was splitted up in a first half (1983-1987) and second half (1988-1993) to study an eventual trend in the management of MM.

RESULTS

The most frequent diagnoses were: thymoma (21%), malignant lymphoma (18%) and mediastinal sarcoidosis (14%). 43% of the MM were localized in the anterior, 46% in the middle and 7% in the posterior mediastinum. Thoracic pain, cough and dyspnoea represented the most common symptoms, leading to an invasive diagnostic procedure. 25% of the patients had no symptoms. The mortality and morbidity rate of all interventions was 3.4% and 18.7% respectively and concerned almost nerval injuries and postoperative respiratory failure. The percentage of direct tumor excisions increased from 21% during the first half of the period to 40% during the second half of the period, whereas diagnostic surgical interventions decreased from 57% to 44%. The percentage of total excisions after previous surgical biopsies decreased from 22% to 16%. In spite of the introduction of high resolution CT scan and MRI techniques during this time period no significant change in the use of presurgical diagnostic procedures was obvious. Fine needle biopsies and bronchoscopies were performed less frequent in the second half in comparison to the first half (11%, 7%, 29%, 13% respectively). From 123 patients with neoplastic disease data were available for long-term results. 35 had benign and 83 malignant histologies, in five cases dignity was unclear. 54% of these patients were disease-free at follow-up time, 10% had local recurrency or distant metastasis and 37% died during the observed time period.

CONCLUSIONS

Surgical biopsy seems to remain the most important investigation for a successful interdisciplinary approach to MM. Overall morbidity and mortality rate of mediastinal surgery might appear remarkable but has to be related to the favorous long-term results after different individual treatment modalities in patients with mediastinal masses.

Cytostatic lung perfusion by use of an endovascular blood flow occlusion technique

BACKGROUND

Different modalities of cytostatic lung perfusion were compared regarding plasma and tissue drug concentrations to assess the efficacy of an endovascular blood flow occlusion technique.

METHODS

A cytostatic lung perfusion study with doxorubicin hydrochloride was performed on large white pigs (n = 12). Plasma and tissue concentrations of doxorubicin were compared for isolated lung perfusion with open cannulation (ILP), blood flow occlusion perfusion with open cannulation of the pulmonary artery alone (BFO), and intravenous drug administration (i.v.). In a fourth group, thoracotomy-free BFO perfusion was performed by endovascular balloon catheterization of the pulmonary artery (endovascular BFO). The 3 animals in this group were used to compare the doxorubicin-perfused pulmonary tissue with the contralateral nonperfused lobes after 1 month.

RESULTS

The mean lung tissue doxorubicin concentration at the end of perfusion was 19.8 +/- 1.6 microg/g after ILP, 27.6 +/- 2.2 microg/g after BFO (p = not significant), and 3.0 +/- 0.8 microg/g after i.v. perfusion (p < 0.01). Whereas doxorubicin was not detectable in the plasma in the ILP group, concentrations ranged from not detectable to 0.44 microg/mL in the BFO group and from 0.31 to 0.84 microg/mL in the i.v. group (p < 0.05). Mean myocardial tissue concentration was not significantly different after BFO than i.v. perfusion (1.1 +/- 0.5 microg/g and 1.8 +/- 0.1 microg/g, respectively). In the endovascular BFO group, balloon-blocked pulmonary artery perfusion was successfully performed in all animals, and after 1 month, lung tissue showed no cytostatic-induced histologic changes.

CONCLUSIONS

Compared with ILP, BFO cytostatic lung perfusion produced an insignificantly higher lung-tissue concentration, corresponding to a sixfold to ninefold higher level than after i.v. perfusion. Plasma drug levels during BFO perfusion were lower than during i.v. perfusion. Endovascular BFO may be a promising technique for repeated cytostatic lung perfusion.

Isolated lung perfusion: single-pass system versus recirculating blood perfusion in pigs

BACKGROUND

Cytostatic isolated lung perfusion has been advocated for treating pulmonary metastasis of soft tissue sarcoma. Different techniques of isolated lung perfusion have been developed.

METHODS

Isolated lung perfusion with and without doxorubicin was performed on white pigs during 15 minutes either by a single-pass system (n = 7) or by a recirculating-blood perfusion system (n = 7). Three animals with endovenous drug application served as controls. Leakage was assessed using isotopic tracers. Perfusion-induced lung tissue injury was determined by postperfusion chest radiographs, by angiotensin-converting enzyme-to-protein ratio in the plasma and in the bronchioalveolar lavage fluid, and by wet-to-dry weight ratio and histologic examination of lung biopsy specimens at 20 and 50 minutes. Doxorubicin concentration in lung tissue and plasma was compared between the three study groups.

RESULTS

All isolated lung perfusion studies were successfully performed without significant systemic leakage (< 0.6%). Wet-to-dry weight ratio was significantly lower after single-pass as compared with recirculating-blood perfusion and endovenous drug application at both time points (5.0 +/- 1.1 and 5.3 +/- 0.8 for single-pass versus 6.6 +/- 1.1 and 6.9 +/- 0.5 for recirculating-blood versus 6.6 +/- 0.2 and 5.9 +/- 0.7 for the control group, respectively; p < 0.05). Angiotensin-converting enzyme-to-protein plasma ratio in the single-pass group was significantly lower only at 20 minutes (6.3 +/- 2.4 versus 9.3 +/- 1.0 versus 9.7 +/- 1.9, respectively; p < 0.05) but not at 50 minutes. Angiotensin-converting enzyme-to-protein ratio in bronchoalveolar lavage fluid, histology of lung biopsy specimens, and chest radiographs did not differ significantly between the three groups. Doxorubicin lung tissue concentration was not significantly different after single-pass (17.5 micrograms/g) and recirculating-blood perfusion (21.9 micrograms/g), but was significantly higher than after endovenous drug application (3.0 micrograms/g; p < 0.01).

CONCLUSIONS

Both isolated lung perfusion techniques resulted in a sixfold to sevenfold higher doxorubicin lung tissue concentration than after endovenous application. Isolated lung perfusion-induced lung injury was similar for both techniques, but recirculating-blood perfusion appeared to result in more acute lung injury and was technically more demanding than single-pass perfusion.

Video-assisted thoracoscopic surgery for fibrinopurulent pleural empyema in 67 patients

BACKGROUND

The roles of different drainage procedures in the management of empyema have to be redefined now that video-assisted thoracoscopic surgery (VATS) has been introduced. The debridement of fibrinopurulent stage II empyema with the use of VATS was assessed prospectively in regard to control of infection and restoration of pulmonary function.

METHODS

Between January 1992 and May 1996, all patients at our institution with fibrinopurulent empyema that did not respond to chest tube drainage and antibiotic therapy were treated by debridement with the use of VATS. The patients were followed up prospectively by clinical and radiologic assessments 3 and 6 months after the operation and by spirometry 6 months after the operation.

RESULTS

Video-assisted thoracoscopic surgery was initiated in 67 patients, but conversion to open decortication was required because of the finding of advanced disease in 19 patients (28%). Forty-eight patients underwent successful debridement with the use of VATS. The mean operative time was 82.1 minutes (range, 50 to 135 minutes), the mean duration of postoperative chest tube placement was 4.1 days (range, 2 to 8 days), and the mean duration of postoperative hospitalization was 12.3 days (range, 4 to 42 days). No wound infections were observed during the postoperative course. Both the 30-day mortality rate and the recurrence (ie, need for thoracotomy) rate were 4%. The mean predicted vital capacity was 84.8% +/- 14.9% and the mean predicted forced expiratory volume in 1 second was 88.6% +/- 19.2% 6 months after the operation.

CONCLUSIONS

Debridement with the use of VATS is safe and efficient for stage II empyema, but open decortication should be used for more advanced disease.

Role of thromboxane and leukotriene B4 in patients with acute respiratory distress syndrome after oesophagectomy

We have studied prospectively the clinical course and serum concentrations of thromboxane B2 (TxB2) and leukotriene B4 (LTB4) in patients developing adult respiratory distress syndrome (ARDS) after oesophagectomy. The clinical course was assessed according to a validated ARDS score, and intra- and postoperative measurements of TxB2 and LTB4 in pre- and post-pulmonary blood were performed in 18 patients undergoing oesophagectomy for oesophageal carcinoma and 11 control patients undergoing thoracotomy and pulmonary resection. Six of 18 patients undergoing oesophagectomy, but no control patient, developed ARDS. The ARDS score was highest on day 8 after operation. Only patients with ARDS had a significant postoperative increase in post-pulmonary, but not pre-pulmonary, TxB2 concentrations (P < 0.05 vs patients without ARDS). This study provides evidence that TxA2, originating from the lungs, was associated with the development of ARDS after oesophageal resection. In view of the high incidence of ARDS after oesophagectomy (10-30%), prophylactic treatment of patients undergoing oesophageal resection with clinically applicable thromboxane synthetase inhibitors may be warranted.

VATS-guided epicardial pacemaker implantation. Hand-sutured fixation of atrioventricular leads in an experimental setting

BACKGROUND

In neonates and infants epicardial stimulation may be preferred to endocardial stimulation because of growth-associated lead problems and the risk of vascular complications associated with transvenous electrodes. This study analyzes the feasibility of atrioventricular implantation of a new epicardial lead using the video-assisted thoracic surgical (VATS) technique in an animal model.

METHODS

Bipolar steroid-eluting epicardial leads were implanted in seven young white pigs. In five animals bipolar atrial and ventricular pacing leads (n = 10) were inserted and fixed by the VATS technique, while two animals served as controls and underwent implantation through anterolateral thoracotomy. Surgical feasibility, pacing, and sensing thresholds of the leads as well as hemodynamic parameters during pacing were studied. Histological changes beneath the electrodes were evaluated 1 week after the implantation.

RESULTS

All animals survived the pacemaker lead implantation. One animal which underwent thoracotomy died because of irreversible ventricular fibrillation induced by rapid ventricular pacing. One animal in the VATS group exhibited intraoperative herniation of the heart through the pericardial window. All animals with left-sided VATS implantations demonstrated good individual pacing and sensing threshold values. The mean cardiac output was 1.6 times higher during AAI-mode pacing as compared to VVI-mode pacing at a heart rate of 140/min. One animal died postoperatively due to respiratory failure. No displacements of the pacemaker leads were observed in the survivors.

CONCLUSION

While VATS-guided implantation of epicardial, atrial, and ventricular leads is feasible, technical improvements of the system are mandatory for safe clinical application.

[Surgical aspects of mycobacterioses. Evolution during the last 20 years]

INTRODUCTION

Tuberculosis remains one of the major infectious diseases. Its incidence has grown in immigrants and in immunosuppressed patients, and, moreover, cases of drug resistance are on the increase. The goal of this study was to analyze the implications of these new developments and surgical experience in our patients.

METHODS

The cases of 104 patients with tuberculosis hospitalized between 1975 and 1995 were reviewed retrospectively.

RESULTS

22% of the patients (23/104) were immigrants. No HIV-positive patients were described but association with debilitating diseases was frequent. Diagnosis was chiefly by histology. The culture was positive in only 30/104 patients (29%). Drug resistance was seen in only one patient (1%). 72/104 patients (69.2%) presented with an infection of the pulmonary parenchyma, 21/104 (20.2%) with pleural tuberculosis including tuberculous empyema, 3/104 (2.9%) with tuberculosis of the chest wall and 8/104 (7.7%) with mediastinal tuberculosis. Surgery was performed in 84/104 patients (80.8%). The chief indications were suspected carcinoma in 39/84 cases (46.4%), destroyed lung in 11/84 (13.1%), empyema combined with bronchopleural fistula in 10/84 (11.9%), enlarged mediastinal lymph-nodes of unknown dignity in 7/84 (8.3%), recurrent pleural effusion in 5/84 (5.9%) and bronchial stenosis in 4/84 (4.8%).

CONCLUSION

The number of surgical patients with tuberculosis has remained fairly stable over the last 20 years, but the proportion of immigrants has grown since 1990. Thoracoscopy is playing an increasingly important role in the diagnosis and surgical treatment of tuberculosis (recurrent pleural effusion, resection of peripheral pulmonary nodules turning out to be tuberculoma).

[Blunt abdominal trauma with lesion of the abdominal aorta--a case report]

A 58-year old lady, involved in a head-on motor vehicle crash suffered a severe intestinal injury associated with an intimal flap lesion of the distal abdominal aorta. Thrombotic occlusion of the aortic bifurcation with clinical evidence of lower extremity ischemia was noted. The management of blunt injury to the abdominal aorta is discussed with special regard to placing prosthetic material in a potentially infected field.

Long-term follow-up of patients with operative stabilisation of a flail chest

The outcome is reported of patients after external chest wall stabilisation for respiratory insufficiency due to a traumatic flail chest. Since 1990, all patients with a flail chest causing respiratory insufficiency despite peridural analgesia and without further reason for prolonged mechanical ventilation underwent osteosynthesis of the chest wall using the AO-technique with 3.5 mm thick reconstruction plates, and were prospectively followed-up by use of clinical and radiological evaluation. 23 patients underwent external chest wall fixation between 1990 and 1996 and were followed for a mean time of 28 months. 2 patients died after the operation, giving a 30-day-survival rate of 91.3% 21 patients survived and were extubated and transferred to the ward after a mean time interval of 3.9 and 7.8 days, respectively. 95% of the survivors revealed a 100% working capacity at assessment and 86% returned to preoperative sports activities without complaining of chest wall or shoulder girdle pain or dysfunction. External chest wall fixation appears to be an attractive alternative to prolonged intubation and mechanical ventilation for selected patients with flail-chest respiratory insufficiency despite peridural analgesia, providing they do not require prolonged intubation for other reasons.